308 THE SCIENTIFIC PAPERS OF 



was one and a-quarter ton of fuel per ton of iron. Now, in 

 dividing the one with the other, it would be found that he 

 claimed only 25 per cent, of the theoretical result. Mr. Krantz, 

 in his investigation of his regenerative gas furnace, gave him 

 credit for utilizing from 15 to 20 per cent, of the theoretical heat 

 residing in fuel in heating iron, but he (Mr. Siemens) claimed 

 25 per cent, in the rotative furnace, because fully one-half of the 

 work was done by reaction of the heated oxygen upon the car- 

 bonic oxide produced there and then in the furnace, and upon 

 that portion there was no sensible loss by refrigeration in cooling 

 tubes or through leakage. Mr. Bell, when he visited his (Mr. 

 Siernens's) little works at Birmingham, had seen the reaction 

 within the rotator going on for a considerable time without any 

 gas being admitted from the gas-producers, showing that the 

 carbonic oxide generated within the mass sufficed to produce the 

 requisite amount of heat to support the process. He (Mr. S.) 

 therefore believed that he should be borne out by practical experi- 

 ence when he asserted that one ton and a-quarter of fuel would 

 suffice for producing a ton of iron. With regard to the quality of 

 that iron, he had already stated in the paper, that it was excellent 

 material for being transferred to the melting furnaces in order to 

 produce steel, being almost entirely free from sulphur and phos- 

 phorus, and although the material produced had not yet been 

 practically proved for iron-making, he felt pretty confident of 

 ultimate success in this direction also. The reason why sulphur 

 and phosphorous did not combine with the iron was that they 

 were in an oxidised condition in the ore and combined with other 

 substances, and that the reducing action of the apparatus was 

 insufficient to move them. If the reaction was insufficient for 

 their reduction, then there was no reason why they should be 

 present at all in the iron, and in that respect the direct process 

 claimed an advantage over the blast furnace, where the reducing 

 action was so energetic that everything reducible was brought 

 into combination with the iron. He thought he had now touched 

 upon all the points referred to in the discussion, and had only to 

 thank them for the patient hearing they had given him. 



